Figure 4.

Scanning electron microscopy showing the large view of root vascular cylinder of susceptible and tolerant soybean cultivars when inoculated with P. sojae. (A) Cross section of the non-infected susceptible soybean cultivar, (B) Cross section of the infected susceptible soybean cultivar, (C) Cross section of the non-infected tolerant soybean cultivar, (D) Cross section of the infected tolerant soybean cultivar. The vascular cylinder of the susceptible cultivar contained hyphae while the vascular cylinder of tolerant cultivar shows the presence of occluding materials. Green arrows denote hyphae, white arrows denote the presence of unknown debris in cortical cells, red arrows denote the presence of occluding materials and yellow arrows denote the presence of vermiculite. Bars: (A–D) 30 µm.